Transcript CSCI 3333 Data Structures Today`s Objectives

Welcome
 CSCI/CINF 4230 Web Application Developement
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Section 02 Tue., 7:00–9:50 p.m.
 Instructor: Charles Moen
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Email – [email protected]
Web page – http://sce.uhcl.edu/moenc
Office – Delta Building 232
Office hours
– Tue., 5:00–7:00 p.m.
– If the hall door is locked, phone me at (281) 283-3848
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Home – 281-796-2820
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CSCI/CINF 4230
 Client-side Web development
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HTML, XHTML, Cascading Style Sheets (CSS),
JavaScript
 Server-side Web development
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ASP.NET, C#
 Server-side database access
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ASP.NET, C#
 Other basic topics in Web development
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HTTP protocol, parameter passing, session tracking,
cookies
• Web 2.0
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26-Aug-2008
Today’s Objectives
 Class roster
 Course overview
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Required textbooks
Web site
Syllabus and schedule
Hosting your web sites for this course at UHCL
How to succeed
 Basic concepts
 Web 2.0
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Course Overview
Required Textbooks
David Schultz and Craig Cook,
Beginning HTML with CSS and XHTML:
Modern Guide and Reference.
Apress, 2007. ISBN 978-1-59059-747-7
Matthew MacDonald,
Beginning ASP.NET 3.5 in C# 2008: From
Novice to Professional, Second Edition.
Apress, 2007. ISBN 978-1-59059-891-7
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Course Overview
Recommended Reference Books
Stephen Spainhour and Robert Eckstein (ed.),
Webmaster in a Nutshell, 3rd Edition.
O’Reilly, 2002. ISBN 978-0-59600-357-9
Other books are listed in the “FAQs” page for
this class
Safari Books Online by O'Reilly
http://safari.oreilly.com/
 You can access Safari from any PC inside UHCL
campus network.
 Provides the full text of hundreds of books
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Course Overview
Course Web Pages
 Course page
http://sce.uhcl.edu/moenc/csci4230fall08/index.html
 Schedule
http://sce.uhcl.edu/moenc/csci4230fall08/schedule.html
 Syllabus
http://sce.uhcl.edu/moenc/csci4230fall08/syllabus.html
 FAQs
http://sce.uhcl.edu/moenc/csci4230fall08/resources.html
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Course Overview
Hosting Your Web Site
 The dcm server is used to host Web sites for UHCL
courses
 You will get an account on this server, and your
homework must be done on it
 dcm.uhcl.edu
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Operating system: Windows Server 2003
Web server: IIS6
http://dcm.uhcl.edu/yourUserName
Files for your Web pages go in the “pages” folder
The “db” folder has an Access database file, “db.mdb”
 Krishani Ekanayake is the administrator
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[email protected]
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Course Overview
How to Succeed
 Expect to spend 10–15 hours per week on this class
 Use a text editor to write the code, and write a lot of code
 Read other peoples’ programs
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After grading is finished, post your homework on your home page
 Homework assignments
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Start them early, and hand them in on time
Check the requirements and make sure
nothing is missing
 Team project
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Select your team mates
 Attend the classes & participate
 Read the book and the resources
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Basic Concepts
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Basic Concepts (Dougherty, Howe, Tyson)
The Internet
 A global network of interconnected networks
 Based on technology developed in the 1960’s
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ARPAnet, the first version, was funded by the U.S. Department of
Defense in a quest to implement a computer network that could survive a
nuclear bomb attack – if part of the network was destroyed, then routers
would direct packets through the surviving paths
(ARPAnet = Advanced Research Projects Agency Network)
• Goal: a robust network of many computers for sharing scientific and
military data
• Initially, ARPAnet connected only four computers at UCLA, Stanford
Research Institute, UCSB, and the University of Utah.
• Mid 1970s, many government agencies and universities were connected;
Early 1990s, private and commercial networks were added
 No one owns the Internet
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The Internet Society, a 1992 non-profit group, oversees its policies and
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protocols
Basic Concepts (http://www.internetworldstats.com)
Growth of the Internet
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Basic Concepts (Dougherty, Howe, Tyson)
The Internet
(Continued)
 General-purpose network
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TCP/IP - protocols for sending packets of data on the network
• Many services run on the Internet
– email
– FTP
– telnet
– World Wide Web (just one service that uses the Internet)
 Every computer that connects to the Internet is already part
of a smaller network
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When you connect to the Internet at home, you become part of your
Internet Service Provider’s (ISP) network
• At work or at school, your computer connects to the Internet through
the Local Area Network (LAN)
• Thus, the Internet is a network of networks
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Basic Concepts (Tyson; Wikipedia)
Internet Infrastructure
Point of Presence
is the physical connection to
the Internet used by the ISP
(servers, routers, switches)
Internet Service Provider
is a company that provides
access to the Internet
Network Access Point
Four physical facilities for
data exchange between
service providers. Now
replaced by Internet
Exchange Points (IXP)
(network switches)
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Basic Concepts (Berners-Lee, Dougherty, Howe, Tyson, Wikipedia)
World Wide Web
“A system of interlinked hypertext documents accessed via
the Internet” - Wikipedia
 Created by Tim Berners-Lee
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In 1989, proposed it as a way to share documents over a network while
he was working at CERN (European Laboratory for Particle Physics)
Originally conceived as just a collection of shared documents
Based on hypertext – links within the text that link to other text
By 1990, built the first Web server, named “httpd,” and the first Web
browser, named “WorldWideWeb”
His work was released to the public in 1993
 World Wide Web Consortium (W3C)
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Standards organization for the Web
• Founded by Tim Berners-Lee
Sir Tim Berners-Lee
from www.w3c.org/People/Berners-Lee
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Basic Concepts (Guelich)
How does the Web work?
The Web uses a client-server architecture
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A Web browser,
such as FireFox
is the client
Web server software,
such as Apache or IIS
is the server
The browser sends an
HTTP request over
the Internet to the
server
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The server sends an
HTTP response to the
browser containing the
HTML text
The browser interprets the
HTML and displays it as a
Web page
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The server examines the
request to determine
what document to
return, index.html in this
example
GET /index.html HTTP/1.1
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Basic Concepts (Guelich)
Client-server Architecture
Web application development technologies:
Web server software,
such as Apache or IIS
is the server
A Web browser,
such as FireFox
is the client
HTTP
Client-side
Server-side
HTML
XHTML
CSS
JavaScript
ASP.NET
C#
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Basic Concepts (Doughterty, Netcraft)
Web Server
Server software
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Installed on a computer connected to the Internet
Often the computer that runs the server software is
referred to as a “Web server”
Manages a collection of HTML documents, as well as
documents in other languages, such as C#
Manages and “serves” the clients’ requests for the
documents
Two Web server programs dominate the market share today
• Apache
• Microsoft
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Basic Concepts (Netcraft)
Web Server
Netcraft, June 2008 Web Server Survey. (2008). [Online]. Available:
http://news.netcraft.com/archives/web_server_survey.html
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Basic Concepts (Schultz)
User Agents
Software that interprets HTML
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Many different devices can access the Web
• Computers, PDAs, cell phones, game consoles,
appliances
Web browser
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The most familiar user agent
• Graphical Web browser – pages rendered with
styled text, colors, and images
• The most-popular browsers
– Microsoft Internet Explorer
– Firefox
– Safari
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Basic Concepts (Ding, Spainhour, Schultz)
URL
Uniform Resource Locator
The address of a document on the Web
http://sce.uhcl.edu/moenc/index.html
Protocol
Rules for moving
data over the
Internet
Host name
or IP address
following by an
optional port
number, e.g.
Path to the document
The root directory in this path is
defined by the server, and may not
be the same as on the host’s file
system
sce.uhcl.edu:80
The human-readable domain name is translated
to a machine usable IP address by the Internet’s
Domain Naming Service servers
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Indicates the type of file.
If there is no document name in
the URL, the server is usually
configured to use “index.html”
or “default.html”
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Basic Concepts (Ding, Spainhour)
URL for local development
The loopback address
http://127.0.0.1
http://localhost
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Basic Concepts (Siegal, Ding)
Web Design Evolution
First Generation
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Plain, mostly text
• Single column
• Presentation (appearance) set by
browser defaults
– Gray background with black text
– Links were underlined and in color
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Emphasis on structure, not design
– Few images
– Horizontal rules
– Bullet lists
From Wikipedia
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Often created by programmers, not designers
• Slow modem connections were common
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Basic Concepts (Siegal, Ding)
Web Design Evolution
Second Generation
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Netscape extensions
to HTML introduced
– <table>
– JavaScript
– The <blink> tag
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Designers usually
controlled the presentation
• Some common features
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White backgrounds
Banners across the top of the page
Icons and graphic text for headings
Graphic buttons with beveled edges
Tiled images in the background
Animated gif graphics
From the Internet Archive WaybackMachine
www.jpmorgan.com, June 30, 1998
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Basic Concepts (Siegal, Ding)
Web Design Evolution
Second Generation (cont.)
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Structure
– Main, graphic-intensive home page
– Menus and button bars for navigation
– Tables, introduced by Netscape, were
often used to organize the page into
columns
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Many sites were well-designed
– The best ones showed that the designers
were concerned about legibility and
communicating clearly to the visitor
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Many sites were garish and
ugly
– The worst second generation sites used
technical tricks, such as animated gif
icons just because they were “cool”
From the Internet Archive WaybackMachine
www.uiuc.edu, March 03, 1997
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Basic Concepts (Siegal, Ding)
Web Design Evolution
Third Generation
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E-commerce
• Database-driven
• Clever visual design
based on a theme
– Tables used extensively
– CSS used for presentation
– Designed to involve users
with the site
– Often started with
a splash screen
From the Internet Archive WaybackMachine
www.klutz.com, Feb 02, 2001
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Basic Concepts (Siegal, Ding)
Web Design Evolution
Fourth Generation
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Sophisticated visual design
– Presentation is designed with div elements,
defined with CSS, not tables
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Most sites use server-side
software
– Multi-tiered on the server side
– Database driven
– Possibly with web services
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http://www.ncsa.uiuc.edu
http://www.jpmorgan.com
http://www.uiuc.edu
http://www.klutz.com
New technologies
– AJAX and client-side software
– Flash, Silverlight, Adobe AIR
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Big focus is web usability and
accessibility
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Basic Concepts (Koch, Ding)
Accessibility and Usability
 Accessibility
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Your Web site should be accessible to anyone under
all circumstances
Issues:
– Users with diminished eyesight must use screen readers
– Some users don’t use a mouse; they may be partially disabled
– Some users disable JavaScript
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Enhancing your page with features that make it easier to use
Examples:
– Show a form field only when it is needed by the user
– Make important topics easy to find
– Keep the user interface simple
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Web 2.0
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Web 2.0 (O’Reilly, Ding, Yue)
What is Web 2.0?
 A phrase by Tim O’Reilly
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Published online, “What Is Web 2.0, Design Patterns
and Business Models for the Next Generation of
Software”
September 2005
 Web 2.0 Conference
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Now in its fifth year, called “Web 2.0 Summit”
 “Web 2.0” and the conference were created by
brainstorming about what is important to the Web
after the collapse of the “dot-com bubble”
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Web 2.0 (O’Reilly, Ding, Yue)
What is Web 2.0?
 A buzzword – difficult to understand because
there’s no consensus on its meaning
 Generally refers to a new phase of Web
business models and technologies
 An attempt to identify characteristics of Web
businesses that survived the dot-com crash
 It is not a new standard for the World Wide Web
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Web 2.0 (O’Reilly, Ding, Yue)
Web 1.0 vs. Web 2.0
Web 1.0
Web 2.0
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Britannica Online
Publishing
Personal websites
Screen scraping
Directories
Netscape
Wikipedia
Participation
Blogging
Web services
Folksonomies
Google
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Web 2.0 (O’Reilly, Ding, Yue)
Some Web 2.0 Characteristics
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Web-centric
Data intensive
Open architecture for participation
Social networking
Lightweight software development
Perpetual beta
Business model takes advantage of the
long tail
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Web 2.0 (O’Reilly, Ding, Yue)
Software Development
Web 2.0 Style
Microsoft – “old school”
 Traditional sales and
licensing
 Heavy weight desktop
software
 Long update cycle
 Tens of versions
 Millions of copies
 Backward compatible
 Value is in the software
Google – Web 2.0
 Services through the Web,
no sales, no licensing
 Universal thin client
(browser)
 In “perpetual beta” – will be
improved incrementally over
the course of time
 One version
 One copy; hidden massive
server farms
 Open standards and public
API
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 Value is the data
Web 2.0 (Anderson, Wikipedia)
The Long Tail
and Web 2.0
Chris Anderson (2005)
http://www.wired.com/wired/archive/12.10/tail_pr.html
 “The future of business is selling less of more”
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“Make everything available”
Keep prices as low as possible
Help the buyers find what they want
The Long Tail
 Amazon.com vs. Barnes and Noble
 Netflix vs. Blockbuster
 Strategy differences
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Popularity
“Blockbuster” strategy is to sell a large number of
very popular items
“Long Tail” - Sell small quantities of obscure items
to a large number of people
Most popular
Least popular
Products are ranked by popularity
on the horizontal axis
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Web 2.0 (Elberse)
Food for Thought
about The Long Tail
Anita Elberse, “Should You Invest in the Long Tail?”. Harvard Business
Review, 2008.
http://harvardbusinessonline.hbsp.harvard.edu/hbsp/hbr/articles/article.jsp?ml_action=getarticle&articleID=R0807H&ml_issueid=BR0807&ml_subscriber=true&pageNumber=1&_requestid=57934
 Anita Elberse investigated actual sales patterns in the
music and home video industries to test whether the
Long Tail theory has a good potential for profit
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The Long Tail theory might work, but in limited cases
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The blockbuster strategy is still the most reliable
Web 2.0 (O’Reilly, Ding, Yue)
Some Web 2.0 Technologies
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XML
AJAX
Web Services API
Social networking
Web syndication, e.g. RSS
Folksonomies – collaborative tagging
Ruby on Rails
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Web 2.0 (O’Reilly, Ding, Yue)
Some Web 2.0 Applications
 Flickr
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http://www.flickr.com
Select “Explore” to see a “tag cloud”, an example of a folksonomy where the
most popular tags are in a larger font size
 Google Docs
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Cloud computing – software is provided as an Internet service
http://docs.google.com/Presentation?id=dg787rt7_337dpzzgbdd
 Del.icio.us
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Storing, sharing, and discovering web bookmarks
 GMail
 MySpace.com
 Bit Torrent
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Web 2.0 (McAllister)
Food for Thought
about Web 2.0 technologies
Is the Web still the Web?
Neil McAllister (June 3, 2008)
http://weblog.infoworld.com/fatalexception/archives/2008/07/is_the_web_stil.html
“Given the growing number of data types and file formats being
transmitted over HTTP and the increasing complexity of the
applications that make use of them, is today’s Web really still the Web?
Or is it morphing into something else?”
 Tim Berners-Lee – the Web as information storage based on hypertext
 Web documents – text marked up with HTML; linked to other documents
 Today:
• Rich client interface
• Technologies like Ajax, Flash, MS Silverlight, Google Web Toolkit, cloud
computing
• Is it inappropriate to force these technologies to use the Web infrastructure?
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References
Chris Anderson (2005). “The Long Tail”. [Online]. Available:
http://www.wired.com/wired/archive/12.10/tail_pr.html
Berners-Lee, Tim. (1990). “WorldWideWeb: Proposal for a HyperText Project”. [Online]. Available:
http://www.w3.org/Proposal
Berners-Lee, Tim. “Tim Berners-Lee” (Homepage). [Online]. Available:
http://www.w3.org/People/Berners-Lee
Ding, Wei, “Introduction of Web Application Development” UHCL lecture slides, 2008.
Dougherty, Dale and Richard Koman, The Mosaic Handbook for Microsoft Windows. Sebastopol, CA:
O’Reilly and Associates, Inc.,1994.
Howe, Walt. (2007). “A Brief History of the Internet”. [Online]. Available:
http://www.walthowe.com/navnet/history.html
Koch, Peter-Paul, PPK on JavaScript. New Riders, 2007.
O'Reilly, Tim. (2005). “What Is Web 2.0". [Online]. Available:
http://www.oreillynet.com/pub/a/oreilly/tim/news/2005/09/30/what-is-web-20.html.
Tyson, Jeff. “How Internet Infrastructure Works”. [Online]. Available:
http://computer.howstuffworks.com/internet-infrastructure.htm
Siegal, David, Creating Killer Web Sites (Second Edition). Hayden, 1997.
Yue, Kwok-Bun, “Web 2.0, Research and You”. Presentation at UHCL, 2006.
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